Construction machines for soil compaction, or soil compaction machines, are used where an increase of the density of the soil is desired. This relates in particular to the compaction of asphalt, earth, gravel, sand, etc. This is regularly the case, for example, in roadway, path, and route construction, however, this list is in no way to be understood as restrictive. Soil compaction machines frequently comprise a vibration means for this purpose, via which load pulses which compact the soil can be introduced into the surface of the soil. Such a vibration means typically comprises a vibration exciter and a soil contact unit. In particular, vibratory plates having a plate as a soil contact unit and vibration rollers having a hollow-cylindrical roller drum as a soil contact unit can be described as examples of such vibration compactors, which are particularly preferred refinements of the present invention. Such vibration rollers can be self-propelled or manually guided. Specifically, this can relate in particular, for example, to so-called single-drum compactors or tandem rollers. The vibration exciters used in this case are especially developed for the application “compaction of the ground surface” and are optimally adapted to the design conditions and the intended use of construction machines for soil compaction. This relates, in particular, to the design of the vibration exciters usable here with regard to their operating variables, for example, vibration frequency, vibration amplitude, etc.
The vibration exciters used in such soil compaction machines are used to generate alternating load pulses for compacting soil, which are introduced into the soil via the respective soil contact. A vibration roller is known from EP 0704575 B1, in the roller drum of which a vibration exciter s installed which has two parallel imbalance shafts running in opposite directions. These are arranged in the roller drum opposite to one another in relation to the center axis of the roller drum and are connected to one another via a mechanical coupling in the form of a gear drive. The drive of the two imbalance shafts is performed via a motor, which acts on one of the imbalance shafts, while the other imbalance shaft is set into rotation via the gear drive. A vibratory plate and a manually-guided soil compaction roller are known, for example, from EP 2 743 402 A2.
Due to the parallel arrangement of the two imbalance shafts, it is possible to generate oriented vibrations, by changing the phase relation of the two imbalance shafts in relation to one another by means of an adjustment device. The change of the phase relation is performed by an adjustment of the angle position of one imbalance shaft relatively to the other imbalance shaft. For this purpose, for example, a hydraulic axially displaceable adjustment coil is provided on the relevant imbalance shaft, using which an axial control movement is converted into a rotational movement.
The present invention is based on the object of providing a soil compaction machine of the type described above, in which the vibration exciter enables a large number of exciter functions using relatively simple technical means.
This object is achieved in that the drive device of the vibration exciter has two motors, of which a first motor is operationally linked to the first imbalance shaft and a second motor is operationally linked to the second imbalance shaft.